Perera, Anura .C විද්යා විනෝදය - Sarasvi Publisher Nugegoda 2020 - 162p 1 - 2023-11-24 ISBN: 978-955-31-2123-3 Nat. Bib. No.: 0008606 Nat. Bib. Agency Control No.: PER Universal Decimal Class. No.: 530